Apparatus for controlling engine idling speed



Feb. 11, 1958 E. OLSON APPARATUS FOR CONTROLLING ENGINE IDLING SPEED Filed June 15, 1954 2 Sheets-Sheet 1 IN V EN TOR.

43% Q fLMER 01.50

ATTOENEY Feb; 11; 195 8 E. OLSON 2,822,701

APPARATUS FOR CONTROLLING ENGINE IDLING SPEED Filed June 15, 1954 2 Sheets-Sheet 2' IN VEN T OR.

a I 677762 M United States Patent n APPARATUS FOR CONTROLLING ENGINE IDLING SPEED Elmer Olson, Rochester, N. Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application June 15, 1954, Serial No. 436,872

5 Claims. (Cl. 74-472) This invention relates to carburetors for internal combustion engines and more particularly to carburetors provided with mechanism for automatically controlling the engine idling speed under certain operating conditions.

It has been found that under conditions which cause the under-hood temperatures to get considerably higher than normal, the engine does not idle satisfactorily, operating unevenly and tending to stall. This higher than normal under-hood temperature is encountered in the event of prolonged idling of the engine on vehicles equipped with air conditioning apparatus, and, in fact, the difliculty can be encountered in any automotive vehicle on a day when atmospheric temperatures are very high in the event of prolonged idling. Therefore, it has been found desirable, in the event of prolonged idling, to step up the idling speed and this is automatically 'accomplished in the copending application of Olson et 211., S. N. 379,401, filed Sept. 10, 1953, now Patent No. 2,762,235, dated September 11, 1956, by mechanism controlled by the transmission control lever and effective to increase the idling speed whenever said lever is moved to its neutral position.

It is not desired to increase the idling speed when the vehicle is stopped for a brief period, as is generally the case when waiting for a traffic-light, for example. When the idling period is relatively brief, the temperature does not as a rule get high enough to produce any difficulty with respectto the idling operation. Moreover, under these conditions the transmission control lever is usually permitted to remain in drive position. In a vehicle with a synchro-mesh transmission, the clutch is generally disengaged and with an automatic transmission, the position of the control lever is not changed when such a stop is made.

It is the primary purpose of the present invention to provide a simplified means for increasing the idling speed when the engine idles with the transmission control lever in neutral position and this is accomplished by a suction operated member which moves a movable idle stop to a position to increase the opening of the throttle to some extent when the transmission control lever is in its neutral position; When the control lever is in this position, the load on the engine is slightly less than when the lever is set in drive position in a vehicle equipped with an automatic transmission and also with a synchro-mesh transmission the load is slightly less when the control lever is set in neutral than when such lever is set in a gear engaging position with the clutch disengaged. Due to this reduction in load, there is a slight increase in engine speed and this increase in speed will cause a slight increase in engine suction, or partial vacuum maintained between the throttle and the engine which is utilized to move a diaphragm connected to the movable idle stop. Movement of the diaphragm efiects movement of the idle stop in a direction to move the throttle a little further toward open position so as to further increase the engine s eed.

Further objects and advantages of the present inven- 2,822,70i. Patented Feb. 11, 1958 tion will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a side elevation of a conventional carburetor equipped with the device which is the subject of the present invention;

Figure 2 is a detail section through the diaphragm housing; and

Figure 3 is a detail view of the mounting of the stop operating lever; and g Figure 4 is a diagrammatic view, showing the carburetor of Fig. 1 and associated controls.

For convenience of illustration, the device which constitutes the present invention is shown in the drawings as mounted on the housing of a carburetor such as illustrated in the copending application of Olson and Dermond, S. N. 264,136, filed December '29, 1951, now Patent No. 2,771,282, dated November 20, 1956. This carburetor is what is generally termed the four-barrel type, having four separate outlets connecting with four separate passages formed in the intake manifold, but so far as the present invention is concerned, it is entirely immaterial whether the carburetor with which it is associated is of single or plural outlet construction. Also, the specific internal construction of the carburetor is of no importance, so far as the present invention is concerned and, therefore, to simplify the illustration only the outside of the carburetor is shown in elevation.

The carburetor shown is formed of three separate castings, an air inlet casting 2, through which air flows into the carburetor, casting 4 immediately below casting 2, in which the fuel chamber is positioned and in which the mixing chamber, where fuel is mixed with air to form a combustible mixture, is also positioned. The casting 4 is secured to and supported by the outlet or throttle body casting 6, which is provided with the usual attaching flange 8 for securing the carburetor to the intake manifold of an engine 9 in the usual way.

In the casting 6 there are a plurality of primary mixture outlets and a plurality of secondary mixture outlets, one primary outlet 10 and one secondary outlet 12 being indicated by dotted lines. The outlets 10 are controlled by throttle valves 14 and the outlets 12 by throttle valves 16, only one of each of said valves being shown in the drawings. The primary throttles are secured to a shaft 18 and the secondary throttles to a shaft 20, both of which are suitably journalled for rotation in the wall of the casting 6.

The primary throttles 14 are open at all operating speeds and after a predetermined opening movement of such throttles the operation of shaft 18 effects movement of the shaft 20 to open the secondary throttle valves. To effect this operation, the shaft 18 has secured thereto an operating arm 22, having formed therein a slot 24 in which is received the bent-over end 26 of an operating link 28, the other end of which is pivotally connected to an operating arm 30, secured to the secondary throttle shaft 20. In the carburetor shownin the above application the shaft 18 has an operating arm secured to its opposite end which is moved by the usual throttle operating mechanism to rotate the shaft 18 in a counter-clockwise direction in order to effect opening movement of link *28'andmoves-arm30 -in a clockwise direction to open the secondary throttles 16. A spring 32 tends to hold the secondary throttles'closed. The mechanism so far 'described, with the --exception noted, is substantially thesame as that fully shown 'ariddescribedin'the above: mentioned pending application;

The primary throttles 14 occupy a very-nearly closed position for normal idling and this positionis-determined by "an -adjustablestop screw which-engagesa fixed lug projecting from the earburetor 'housing. The stop screw is carried by an arm on the opposite side of the shaft 18 and engagesa lugon the opposite side of the c'arburetor housing. This mechanism is not shown but is of the same construction as shown in the above-"mentioned application. The stop screw is set in adjusted position to give the desired normal idle speed.

As already indicated, means are provided, according to the'present invention, for moving the primary throttles 14 slightly toward open position. when'the engine 9-is idling with the transmission 31 in neutral, such means being operated by engine suction. This mechanism ineludes an adjustablestop screw 40 threaded in an ear '42 extending laterally from a lever 44 pivoted-on a pin'46 secured in any suitable way to a bracket 48 and 'extending laterally therefrom. To prevent any appreciable movement of the lever 44 axially with respect to {the pin -and to hold the parts in proper alignment, any suitable means may be provided. For example, as shown in Fig. 3 the end of pin 46 may be of reduced size, as indicatedat 50, and a nut 52 be screwed thereon 'Wit'n a 4 itable lock washer 54 to hold the nut in place. The screw 40 is adjusted so that its position with reference is arfii 22 is such as to give the desired result.

The supporting bracket 48 is integral with a platess which extends upwardly and at its upper'end 1 tegral with a flat horizontal plate 58 which extends' 'over and is secured by screws '60 to the top of the {fuel hamber which is a part of the casting 2. The pla'tesS'G and 58 form a supporting bracket and a reenforeing rib-62 may be provided to increase the rigidity of the bracket.

Secured to the supporting plate 56 is a diaphragm housing indicated generally by the numeral 70'and foriiied of two sheet metal shells 72 and 74, the circumferential edge of shell 72 being'crimp'ed over the edge or -s'hell74 to form a fluid-tight joint, and a flexible diaphragm-'76 of suitable materialis clamped between the peripheral edges of the shells. Extending into'theshell72'is a sleeve 78 which has a reduced part 80 extending through a central opening formed in shell 72and-also through "the supporting bracket 56, the end of part "80 being 'spu'n over as indicated at 82 to clamp the plate and shell 72 against a shoulder formed-at the junction of the fdiic'Ed part 80 and the enlarged part of the-sleeve. The latter serves as a bushing in which a 'pin 84 connected to the the diaphragm slides, when the engine suction enema. on such diaphragm varies. v 1

The diaphragm and two *r'eenfo'rcing washers 86 and 88 positioned on opposite sidesofthe-diaplirag'm are mounted on a reduced portion of a stud '84 which is riveted as indicated at 90 to hold the parts in assembled position, Positioned between the washer 88 and the 'rivet-he'ad-90 is a cup-shaped washer 92, which receives one end are spring 94 positioned between such washer-and the boltsing 74, such spring being effective to hold the parts in. the position shown in Fig. 2 when there is no sii'ction eifective on the diaphragm. When the parts arefin this position the throttles 14 are closed toan extent {determined by the normal stop which "has beeridescrihe'dfbut is notshownp. 7 r

An adjusting serew ssgas be mounted in any deSirable way in the shell 74, if'desii'ed ahd maybe adjusted to determine the position to which the diaphragm can be moved by engine suction which is communicated'by pipe 98 to the inside of shell 74,.si1'ch pipe being connected to the intake passage'at some "suitable point hetweenthe 4 throttles --14and the engine. The pipe 98 may be connected to shell 74 by any suitable means and as shown, has a flange 100 which is clamped between a nipple 102 secured to the shell and a clamping nut 104 which is screwed on the nipple.

Any increase in suction effective on the diaphragm 76 will move the-throttles 14 toward open position. To this end the stud 84 isfconnected to the upper end of lever 44 by a pin and slot connection, the lever having a-slot 106 into whi'ch apin-llltl'projecting from thestud 84 extends, 'asindi'cated-in. Fig. 1. Obviously, 'a'movement of the diaphragm to the right will move the upper end of lever"44 to the "right andthe stop '40 to the left to efiect counter-clockwise movement of arm 22 and opening movement o'f throttles 14.

The manual operating linkage for the throttles includes a lost motion device adjacent its point of connection with arm22, so-that this -"s'light movement of the throttles canbe eftr'ected withbut' aiiy movement of the throttle operating linkage. As shown, the throttle operating linkage includes-a rod 110 which is connected by suitable operating connections, not shown, to the usual foot operated accelerator pedal. This rod is integral with or suitably connected to a tubular member 112 into which-the-enlarged part'1'14 of a'rod 116 extends. The rod 116'isf'piivotally"connected by a pin118 in a slot lzorormed in the arm 22=and a spring 123'is positioned in the tubular inetiiber 1'12 between the end thereof and the left end easement 114.

The tubiil ar manner 112 has slots 124 'near its right end and tending through these slots is a pin 126 which also extends through a i'iole in the element 114 and is held in position by a cotterpin 128. The spring 123 normally h'olds the-parts in tlie po'sition-shown in Fig. l and when "the accelerator pedal is depressed to open the throttles, the rod 110 is pulled to the left and the 'pin 126 be ir1g intheright end'of the slots, the lihk 116 is also pulledt'o -the -le'ft to open the throttles. When the stop 40 is moved to the left, as previously described, the 'movern'e'n't" of element 114 inerely compresses the spring 123 and-does 'iio't mo've the rod 110 and operating connections extending {from such rod to the accelerator pedal, the usual accelerator return spring being stronger than the spring 123. I

To illustrate the operation of the device, let it be asshared that the engine 9 is idling and the transmission 31, if of the automatic type, is set in drive position by a transmission control lever 131 and'if of the manual control type, is set in some gear engaging position with the clutch disengaged. The throttle will be closed to an extent determined by the ordinary idle stop, or possibly by stop 43, and the transmission gearingis being rotated slowly by the engine. If the transmission control lever 131 isrnov'ed to neutral position, the load on the engine is somewhat reduced, by reason of the fact that the transmission gears are not being rotated. This will cause a slight increase in e'r'igine'speed, and the increase in speed will, inturn, 'c'au sea slight increase in the suction efiective on diaphragm 7o and a slight movement of stop 40 to the-'leftto effect aslightincrease in throttle opening.

It will be understood that when the engine is not operating the usual idle stop, which is not shown, will determine the closed position of the throttle, and when the engine is running the position of the throttle, when idling cold, will be determined by the fast idle stop, as shownin the above-mentioned. When idling'ho't, the throttle position may be determined either by the normal idle stop or'the *sto'p' screw '40.

As the throttle is opened in the manner described, the suction posterior 'tothe throttle begins to fall, for reasons well known. This tends to offset the effect of increased engine speed and after a slight opening movement of the throttle,fthese sheets are balanced and the throttle stops in a slightlyfrnore open position than before the control lever-was shiftedto neutral. The valve stops when the force exerted by suction on the diaphragm is balanced by the spring 94 and this occurs after a slight opening movement of the valve. This opening of the throttle is slight, but enough to eifect sufficient increase in idling speed to obtain satisfactory idling operation. It will of course, be understood that in the particular carburetor shown, the position of both throttles 14 is 'controlled in the manner described but the stop mechanism disclosed can be employed in a single outlet carburetor to control the position of the conventional single throttle valve.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine and having a throttle valve for controlling the quantity of mixture supplied thereto, suction operated means for moving the throttle toward open position for increasing the idling speed of the engine, and a control means movable to difierent positions to control the operation of the vehicle, said control means being movable to a position reducing the load on the engine thereby causing the suction effective on the suction operated means to be increased and the throttle to be moved to a further open position.

2. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine and having a throttle valve for controlling the quantity of mixture supplied thereto, sucion operated means for moving the throttle toward open position for increasing the idling speed of the engine, and a transmission control lever movable to diiferent positions to control the operation of the vehicle, said control lever being movable to a position reducing the load on the engine thereby causing the suction eflective on the suction operated means to be increased and the throttle to be moved to a further open position.

3. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine and having a throttle valve for controlling the quantity of mixture supplied thereto, suction operated means for moving the throttle toward open position in order to increase the idling speed of the engine, a transmission control lever for controlling the operation of the vehicle transmission, said control lever being movable to a position reducing the load on the engine thereby causing the suction effective on the suction operated means to be increased and the throttle to be moved to a farther open position, a manually operable means for actuating said throttle valve, and a lost motion connection in said last named means to permit relatively unresisted movement of said throttle by the suction operated means.

4. An idling speed controlling apparatus as defined in claim 3 in which said lost motion connection comprises telescoping members connected by a pin and slot connection.

5. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, a carburetor for supplying a combustible mixture of fuel and air to said engine and having a throttle valve for controlling the quantity of mixture supplied thereto, suction operated means for moving the throttle toward open position in order to increase the idling speed of the engine, a transmission control lever for controling the operation of the vehicle transmission, said control lever being movable to a position reducing the load on the engine thereby causing the suction effective on the suction operated means to be increased and the throttle to be moved to a farther open position, an operating arm for said throttle, a manually operating connection extended to said arm, a mem ber operable by said suction operated means and also engaging said operating arm to move said throttle toward open position upon an increase of suction, said operating connection including telescoping members connected by a pin and slot connection, whereby movement of the throttle by the suction operated means is not materally resisted by the manual operating connection.

References Cited in the file of this patent UNITED STATES PATENTS 1,886,672 Good Nov. 8, 1932 2,323,202 Christian June 29, 1943 2,362,655 Mallory Nov. 14, 1944 2,377,256 Mallory May 29, 1945 2,551,835 Forman May 8, 1951 2,623,617 Snyder et a1. Dec. 30, 1952 

